Yeap it's been a while. I'm back with another project bike that I'm sure some people will find interesting. I met a very good dirt bike rider that was riding a KTM 550 dirt bike and I was amazed at what he could do with it. The bike was neglected but you couldn't tell once he was riding that beast. It took me by surprise and I knew right then and there I had to have one some day. After a couple of years looking around I finally found one... or it found me you could say. I feel very lucky to have such a fine and mostly complete KTM 540. They are getting harder and harder to find.

Just to start things off today I'm posting the first few pictures I took the day I brought it home.

You can always tell how used or abused a dirt bike it by checking underneath it. If you see dented frame tubing or scratches and marks on the engine cases then you know the bike has been ridden pretty hard.

You can't be too picky with older bikes. Discoloration and a little rust is nothing to worry about. I'm more worried about serious corrosion dents and cracks in the engine cases. This bike is in GREAT shape.

This bike has a monster cylinder. And the right hand drive hub is interesting as well. Supposedly the engine was for sidecars in Europe. The American distributor at the time demanded KTM use that engine in a dirtbike because we crazy Americans wanted CR500 and KX500 type crazy machines. Thank you KTM!

The worst thing about this bike project is that I need to locate some side panels for this 1992 KTM540 DXC. Plastics are pretty hard to come by for this machine. The exhaust looks very good and most all of the parts seem to be in great condition. This is easily the best original 540 / 550 KTM dirt bike I've ever seen. I'm very happy to have such a good head start on this bike.

Here are a few more pics just to show some more things that need attention in the upcoming KTM 540 build. The original sprockets are definitely showing some fatigue but hey it's a 60+ hp engine. It's just amazing that it still has only the original sprockets and chain. This bike has hardly been used.

Then upon further inspection the rear rim has a couple cracks in it but reading on other forums this is totally expected. Apparently the rims produced for KTM were not high quality so they are ticking time bombs. The cracks so far are really small so they will work for a little while. I have another set ready for when these give out but for now I like the original look so I'm running them.

It takes some serious horsepower to pull those sprocket teeth over so hard. The factory 540 countershaft sprocket on the left. To the right is the lightly used replacement I had ready to install next.

Slight cracks in a couple areas. I'm just lucky the rims aren't all bent up and completely ruined. If the bike had been used more than 20 hours they would have been. With the power of this engine I would fully expect these rims to be ruined by now. I got lucky with this very lightly used KTM 540.

Here is another shot of the rim. It's a product made in Norway and they are pretty proud of their work even putting a neat Made In Norway sticker on them. Too bad they turned out to be prone to cracking and are known to fail early. I'll keep using the classic style rims until they give out.

Here is the interesting stock 1992 KTM 540 DXC rear hub and sprocket. The sprocket has a very large inner diameter which is unique to the late 80's and early 90's KTMs. When removed the sprocket is a very peculiar shape that isn't nearly as thick as a standard sprocket. Did they do this to make the hub larger and stronger? It's laughable that they put an aluminum sprocket on the rear of such a powerful bike. Just the fact that the original rear ALUMINUM sprocket is still on this bike means that this bike has very little time on it. I was lucky enough to locate a brand new aftermarket aluminum sprocket on Ebay for pretty cheap. I would have bought a steel sprocket but the one I did see for sale was more money.

I have since adapted a newer KTM rear wheel to this bike without much trouble at all. I am having fun keeping the original stock rear wheel on this bike for now but I have a feeling that the Norway made rim will crack close enough to make me retire the wheel before I wear down the aluminum sprockets. When this setup is retired I will be running a newer KTM rear wheel which has endless sprocket options. Finding the "thin ring" original sprockets is a pain in the butt on Ebay and the options are very limited. They ARe on Ebay but the sellers don't put what style the sprockets are in the listing description. This means that you can't type in a search term in order to list the unique "thin ring" sprockets. You have to actually sift through the pictures looking for a sprocket picture that looks like the older sprockets.

Here is another reason I will be retiring this rear wheel once I use up the aluminum sprockets or they crack enough for me to lose confidence in them: the rear brake disk is a really bad design. This sucker has the disc bolts paired together instead of evenly spaced around the disk. What is going on here?? And the inner part of the brake disk should fall in a groove machined in the outer edge of the hub that it is bolted to. The disk actually is bolted along side the hub. This instead of coming to contact on a typical shoulder groove that is machined into the hub's outer diameter mounting surface. This is a very non-traditional way to mount the disk which puts a whole lot of sheer force on the mounting bolts. I don't intend to over stress the bolts to failure but this design is not a self-centering design where the disk rides in the groove of the hub (and the bolts just hold it in place). No, with this design all the force is applied from the brake rotor to the bolts as they try to hold the disk along side the hub. Not cool.